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Journal Cover Reactive and Functional Polymers
  [SJR: 0.8]   [H-I: 72]   [5 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1381-5148
   Published by Elsevier Homepage  [3040 journals]
  • Pyrocatechol-modified resins for boron recovery from water: Synthesis,
           adsorption and isotopic separation studies
    • Authors: Jiafei Lyu; Zhouliangzi Zeng; Nan Zhang; Hongxu Liu; Peng Bai; Xianghai Guo
      Pages: 1 - 8
      Abstract: Publication date: Available online 2 January 2017
      Source:Reactive and Functional Polymers
      Author(s): Jiafei Lyu, Zhouliangzi Zeng, Nan Zhang, Hongxu Liu, Peng Bai, Xianghai Guo
      Two kinds of pyrocatechols, pyrocatechol (CL) and nitropyrocatechol (NCL), were chosen by the conductive value change (Δ) they cause in the boric acid-polyol solutions, and corresponding modified resins (CL-RESIN and NCL-RESIN) were synthesized by new methodology for effective boron removal and isotopic separation. The optimized boron adsorption occurs at pH=9.06 for CL-RESIN, and pH=6.70 for NCL-RESIN, with the maximum adsorption capacity 0.7886mmol·g−1 and 0.7931mmol·g−1, which were comparable to commercial IRA 743. Boron adsorption on prepared resins was saturated within 12h and can be well described by pseudo-second-order kinetic model. Freundlich isotherm model fits well at low boron concentration while Langmuir isotherm model fits better at high concentration. Furthermore, the boron isotopic separation factors S on two prepared resins are 1.080 for CL-RESIN and 1.140 for NCL-RESIN, which are far higher than all previous results. Boron removal and isotopic separation capacities make it possible that three problems, boron removal, isotopic separation and boron reusability, can be addressed in single adsorption process.
      Graphical abstract image

      PubDate: 2017-01-06T10:27:11Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.016
      Issue No: Vol. 112 (2017)
       
  • Properties of native and oxidized corn starch/polystyrene blends under
           conditions of reactive extrusion using zinc octanoate as a catalyst
    • Authors: Tomy J. Gutiérrez; Vera A. Alvarez
      Pages: 33 - 44
      Abstract: Publication date: March 2017
      Source:Reactive and Functional Polymers, Volume 112
      Author(s): Tomy J. Gutiérrez, Vera A. Alvarez
      Native and oxidized corn (Zea mays) starch/polystyrene (PS) blends containing glycerol as a plasticizer were prepared by reactive extrusion in a twin-screw extruder using zinc octanoate (Zn(Oct)2) as a catalyst, followed by compression molding. Blends were characterized in terms of their: average molecular weight, moisture content, infrared (FTIR) spectra, water solubility, thermogravimetric (TGA) properties, differential scanning calorimetry (DSC) curves, X-ray diffraction (XDR) patterns, stability in acidic or alkaline medium, and microstructural, mechanical and antimicrobial properties. The results clearly show that the catalyst used produced cross-linking between the starch and PS, and that the oxidative modification of the starch increased its reactivity. This was demonstrated by the increase in molecular weight, thermal resistance, and hydrophobicity of films prepared from the oxidized starch/PS plus catalyst. This increase in hydrophobicity of the starch modified systems was due to the carboxyl and carbonyl groups introduced into the starch structure. As a result, phase separation was more obvious, despite the increase in the cross-linking rate between the oxidized starch and the PS. Finally, none of the films showed signs of swelling or antimicrobial activity. Nonetheless, the catalyst exhibited excellent antimicrobial activity against the pathogenic microorganisms evaluated.

      PubDate: 2017-01-14T10:36:15Z
      DOI: 10.1016/j.reactfunctpolym.2017.01.002
      Issue No: Vol. 112 (2017)
       
  • Multi-layer dextran-decorated poly(glycidyl methacrylate)-co-divinyl
           benzene copolymer matrices enabling efficient protein chromatographic
           separation
    • Authors: Kun Zhang; Qiang Li; Hong Fan; Suning Li; Yue Su; Lan Zhao; Yongdong Huang; Dan Wang; Zhigang Zhang; Zhiguo Su; Guanghui Ma
      Abstract: Publication date: Available online 12 January 2017
      Source:Reactive and Functional Polymers
      Author(s): Kun Zhang, Qiang Li, Hong Fan, Suning Li, Yue Su, Lan Zhao, Yongdong Huang, Dan Wang, Zhigang Zhang, Zhiguo Su, Guanghui Ma
      A strategy to prepare natural polysaccharide-decorated pGMA-DVB by grafting dextran groups was proposed for the development of efficient protein chromatographic separation. Prepared pGMA-DVB microspheres were covalently decorated with dextran through a three-step scheme. Firstly, residual vinyl groups on polymer particles were converted to epoxy groups. Secondly, one layer of dextran was covalently coupled on the microspheres by reacting with epoxy groups in solvent. Thirdly, multi-layer dextran was grafted to microspheres in alkali aqueous solutions. The dextran-decorated microspheres named pGMA-DVB-Dextran were characterized by Fourier transform infrared spectra, scanning electron microscope, atomic force microscopy, laser scanning confocal microscope, and protein adsorption experiment. Consequently, compared to several commercial hydrophilic beads such as Sepharose® 4FF and POROS® OH, the permeability and hydrophilicity of the modified microspheres were improved, the contact angle decreased from 153° to 0°, and nonspecific adsorption of proteins was decreased to zero. The covalently drafting amount of dextran onto pGMA-DVB was increased to 241.86mg/mL microspheres, and the dextran layers were stable after washing with 1M HCL/NaOH solutions. Functional ligands such as Protein A or DEAE coupled to pGMA-DVB-Dextran can be conveniently used to separation model protein, IgG or BSA, with >99.5% recovery yield and high dynamic binding capacity, respectively.

      PubDate: 2017-01-14T10:36:15Z
      DOI: 10.1016/j.reactfunctpolym.2017.01.003
       
  • Microgels from microfluidic templating and photoinduced crosslinking of
           cinnamylidene acetic acid modified precursors
    • Authors: D. Ceylan Tuncaboylu; C. Wischke; F. Störmann; A. Lendlein
      Abstract: Publication date: Available online 27 December 2016
      Source:Reactive and Functional Polymers
      Author(s): D. Ceylan Tuncaboylu, C. Wischke, F. Störmann, A. Lendlein
      So far, a number of approaches to synthesize microgel networks have been followed, while only in few cases a detailed control of the network architecture has been possible. Here, the photoinduced [2+2] cycloaddition reaction of cinnamylidene acetic acid (CAA) moieties coupled to four-arm star shaped oligo(ethylene glycol) (OEG) precursors was explored for the creation of microgels with defined polymer network structures. Based on a rational solvent selection and precursor dispersion in glass-capillary microfluidics, microgels could be successfully prepared by the proposed synthesis approach. Model reactions confirmed a quantitative network formation. Therefore, compared to common radical polymerization for microgel crosslinking, CAA-dimerization may be an alternative approach particularly when well defined network structures are desired.

      PubDate: 2017-01-06T10:27:11Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.015
       
  • Chemically modified natural rubber latex - poly(vinyl alcohol) blend
           membranes for organic dye release
    • Authors: Janisha Jayadevan; Rosamma Alex; Unnikrishnan Gopalakrishnapanicker
      Abstract: Publication date: Available online 5 January 2017
      Source:Reactive and Functional Polymers
      Author(s): Janisha Jayadevan, Rosamma Alex, Unnikrishnan Gopalakrishnapanicker
      Novel blend membranes were prepared from chemically modified natural rubber latex (NRL) and poly(vinyl alcohol) (PVA) for release application. Chemical modification of NRL was done by grafting (dimethylaminoethyl methacrylate) (DMAEMA) onto NR particles by using a redox initiator system viz; cumene hydroperoxide/tetraethylenepentamine (CHP/TEPA), followed by dialysis for purification. The grafting was confirmed by dynamic light scattering (DLS), fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance spectroscopy (NMR). The grafted NRL was subsequently blended with PVA to make uniform membranes by solvent casting at 60±2°C. The blend membranes were characterised by FT-IR spectroscopy, X-ray diffractometry (XRD) and thermogravimetry (TGA). Moisture uptake, swelling and water contact angle experiments showed an increased hydrophilicity when the PVA content in the blend membranes was increased. Scanning electron microscopic investigations indicated the formation of pores in the membranes after a leaching cycle. The potential of the membrane for the use in the release application was tested with model organic dyes rhodamine B, methyl orange and fluorescein. Results from the release study indicate that the membranes can be used for the release of cationic dyes.

      PubDate: 2017-01-06T10:27:11Z
      DOI: 10.1016/j.reactfunctpolym.2017.01.001
       
  • Imidazole-substituted ROMP polymers: Post-modification of
           poly(norbornenediester) derivatives with aminolysis reactions
    • Authors: Bengi Özgün Öztürk; Elif Yakut; Elif Ak; Solmaz Karabulut Şehitoğlu
      Pages: 22 - 29
      Abstract: Publication date: February 2017
      Source:Reactive and Functional Polymers, Volume 111
      Author(s): Bengi Özgün Öztürk, Elif Yakut, Elif Ak, Solmaz Karabulut Şehitoğlu
      In this study, ring-opening metathesis polymerization (ROMP) polymers bearing imidazole and morpholine functionalities were synthesized using an efficient and inexpensive post-modification procedure. First, dimethyl-5-norbornene-2,3-dicarboxylate was polymerized (Mn: 130kDa, Ð: 1.23) in the presence of Grubbs third-generation catalysts through ROMP reactions. Second, these ROMP polymers were modified using octylamine, 1-(3-aminopropyl)imidazole, and 1-(3-aminopropyl)morpholine in the presence of catalytic amounts of tin(II)hexanoate; Sn(Oct)2, titanium(IV)isopropoxide; Ti(O-i-Pr)4; and 1,5,7-triazabicyclo[4.4.0]dec-5-ene. Modified polymers were characterized by 1H, 13C NMR, FT-IR, differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. Quantitative conversions were achieved using 1-(3-aminopropyl)imidazole as a modification agent in the presence of 10% Sn(Oct)2.
      Graphical abstract image

      PubDate: 2016-12-19T09:00:32Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.008
      Issue No: Vol. 111 (2016)
       
  • Glycyrrhetinic acid-modified PEG-PCL copolymeric micelles for the delivery
           of curcumin
    • Authors: Runliang Feng; Peizong Deng; Zhimei Song; Wei Chu; Wenxia Zhu; Fangfang Teng; Feilong Zhou
      Pages: 30 - 37
      Abstract: Publication date: February 2017
      Source:Reactive and Functional Polymers, Volume 111
      Author(s): Runliang Feng, Peizong Deng, Zhimei Song, Wei Chu, Wenxia Zhu, Fangfang Teng, Feilong Zhou
      In this study, glycyrrhetinic acid (GA) was conjugated with mono amino poly (ethylene glycol)-b-poly (ε-caprolactone) (H2N-PEG-PCL) with succinate linker to obtain the GA-modified PEG-PCL (GA-PEG-PCL). By way of thin film hydration method, curcumin was encapsulated into GA-PEG-PCL copolymer to form stable micelles with 93.76% of encapsulation efficiency and 11.93% of drug loading capacity. The micelles enhanced curcumin's water-solubility to 1.87mg/ml, being 1.70×105 times higher than free curcumin. X-ray diffraction and FT-IR analysis confirmed the encapsulation of CUR into copolymeic micelles with an amorphous state. Hemolysis datum of blank micelles showed its biocompatibility. Compared with GA-unconjugated micelles, curcumin-loaded GA-PEG-PCL micelles showed slower in vitro release of drug, but they displayed better in vitro cytotoxicity against HepG2 at about 40μM because of its selective accumulation in HepG2 cells induced by GA. The results showed that GA-PEG-PCL copolymer could be a promising drug carrier for liver targeted drug delivery.

      PubDate: 2016-12-19T09:00:32Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.011
      Issue No: Vol. 111 (2016)
       
  • Mechanism of modulus improvement for epoxy resin matrices: A molecular
           dynamics simulation
    • Authors: Wenqing Zhang; Yang Qing; Weihong Zhong; Gang Sui; Xiaoping Yang
      Pages: 60 - 67
      Abstract: Publication date: February 2017
      Source:Reactive and Functional Polymers, Volume 111
      Author(s): Wenqing Zhang, Yang Qing, Weihong Zhong, Gang Sui, Xiaoping Yang
      Theoretical modulus of three kinds of epoxy matrices, including diethylene toluene diamine (DETDA)/4,5-epoxyclyclohexyl-1,2-diglycidyldiformate(TDE85), m-phenylenediamine (MPD)/TDE85 and single-walled carbon nanotube (SWCNT) reinforced DETDA/TDE85 were investigated via molecular dynamics (MD) simulation to establish the structure–property relationships. The flexibility and mobility of molecular chains, the packing ability of cross-linked chain segment, the fraction of free volume of epoxy resins and the cohesive energy density in different epoxy systems were analyzed in detail, respectively. The MD simulation results showed that both the slight modification in the diamine structure and the introduction of SWCNTs can result in significant changes in the microstructure parameters of epoxy matrix, however, the modulus improvement mechanisms through changing curing agents and incorporating SWCNT into epoxy matrix had similarities and differences. The MD simulation method will be of great value in predicting and analyzing some performance closely related to the microstructure parameters for the different cross-linked resin system and its composite materials.
      Graphical abstract image

      PubDate: 2016-12-27T10:16:11Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.014
      Issue No: Vol. 111 (2016)
       
  • A crosslinked bis(amino)-containing polymer as a remarkable support for
           heterogeneous palladium-catalyzed Suzuki-Miyaura reaction
    • Authors: Yiming Wang; Cuifen Lu; Guichun Yang; Zuxing Chen; Junqi Nie
      Pages: 38 - 46
      Abstract: Publication date: January 2017
      Source:Reactive and Functional Polymers, Volume 110
      Author(s): Yiming Wang, Cuifen Lu, Guichun Yang, Zuxing Chen, Junqi Nie
      Through the substitution reaction of hexachlorocyclotriphosphazene (HCCP) and 4,4′-diaminobiphenyl (DABP), a crosslinked polymer HCCP-DABP was synthesized by a conventional and convenient route. Owing to the strong coordination ability of pincer-type bis(amino) scaffold in the matrix, the polymer was successfully used as a support to form stable palladium catalyst complex Pd/HCCP-DABP. The palladium catalyst showed excellent reactivity in Suzuki-Miyaura cross-coupling reaction. In addition, the catalyst can be readily recovered and reused for further transformations at least 10 times without significant decrease in catalytic activity.

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.003
      Issue No: Vol. 110 (2016)
       
  • Synthesis and properties of photocross-linkable carbazole dimers
    • Authors: G. Simkus; A. Tomkeviciene; D. Volyniuk; S.V. Kostjuk; J.V. Grazulevicius
      Pages: 47 - 54
      Abstract: Publication date: January 2017
      Source:Reactive and Functional Polymers, Volume 110
      Author(s): G. Simkus, A. Tomkeviciene, D. Volyniuk, S.V. Kostjuk, J.V. Grazulevicius
      New carbazole-based monomers with two reactive functional groups such as epoxypropyl, oxetanyl and vinyloxethyl were synthesized and their cationic photopolymerization was performed. The monomer containing epoxypropyl groups exhibited the highest conversion in photopolymerization (78%). The monomers and polymers exhibited ability of glass formation with the glass transition temperatures up to 98°C for low-molecular-weight compounds and those observed for polymers ranging from 89 to 150°C. The synthesized derivatives absorb electromagnetic irradiation in the range of 200–390nm with the band gaps of 3.14–3.16eV. The compounds exhibit blue photoluminescence with the intensity maxima at 400nm. The compounds were found to have high triplet energies of ca. 2.78eV. The electron photoemission spectra of the layers of the synthesized compounds revealed ionization potentials of 5.20–5.37eV. The time-of-flight hole drift mobilities of the layers of the compounds exceed 10−5 cm2/V×s at high electric fields.

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.004
      Issue No: Vol. 110 (2016)
       
  • Development of novel antimicrobial films based on poly(lactic acid) and
           essential oils
    • Authors: Marwa Yahyaoui; Oihana Gordobil; René Herrera Díaz; Manef Abderrabba; Jalel Labidi
      Pages: 1 - 8
      Abstract: Publication date: December 2016
      Source:Reactive and Functional Polymers, Volume 109
      Author(s): Marwa Yahyaoui, Oihana Gordobil, René Herrera Díaz, Manef Abderrabba, Jalel Labidi
      Novel biocomposite films based on poly (lactic acid) (PLA) were prepared by incorporating essential oils as active additive with different concentrations (0.5, 1.5, 2 and 5%). Different types of essential oils from Rosemary, Myrtle and Thyme were used. The optical, thermal, mechanical, water vapour permeability and antifungal properties of all films was carried out. The analysis of essential oils by GC-MS showed the presence of terpene and phenolic compounds that are the most important compounds in essential oils. The addition of different essential oils does not affect the colour change of the films significantly. Thermal degradation of studied films showed a small decrease in the initial degradation temperature when the concentration of essential oil increased, however maximum degradation temperature was similar. Thermal analysis by differential scanning calorimetric (DSC) showed that PLA films containing 5% of commercial essential oils of myrtle and thyme could reduce the polymer chain to crystallize. The mechanical properties are improved by the incorporation of essential oils in the PLA matrix. The effect of commercial essential oil of myrtle in the transfer of humidity from the atmosphere to food is low compared with those containing the commercial essential oils of rosemary and thyme. Finally, the addition of 1.5% commercial thyme and 5% natural myrtle increase significantly the antifungal activity against Aspergillus.niger sp.

      PubDate: 2016-09-21T03:29:31Z
      DOI: 10.1016/j.reactfunctpolym.2016.09.001
      Issue No: Vol. 109 (2016)
       
  • Highly conductive and hydrated PEG-based hydrogels for the potential
           application of a tissue engineering scaffold
    • Authors: Yong Seok Kim; Kanghee Cho; Hyun Jong Lee; Sooho Chang; Hyungsuk Lee; Jung Hyun Kim; Won-Gun Koh
      Pages: 15 - 22
      Abstract: Publication date: December 2016
      Source:Reactive and Functional Polymers, Volume 109
      Author(s): Yong Seok Kim, Kanghee Cho, Hyun Jong Lee, Sooho Chang, Hyungsuk Lee, Jung Hyun Kim, Won-Gun Koh
      A PEG-based hydrogel with a high conductivity and water content was synthesized using a two-step sequential polymerization process by in-situ polymerizing poly(3,4-ethylenedioxythiophene) (PEDOT) within poly(4-styrenesulfonic acid) (PSS)-containing poly(ethylene glycol) diacrylate (PEG-DA) hydrogel matrix. A small amount of diluted sulfuric acid (H2SO4) was added as an accelerator to increase the conductivity via reduced polymerization time. Among the various molecular weights (MW) of PEG, PEG-DA with MW 3400 was used for first hydrogel due to its mechanical property and water content. Incorporation of PSS within the PEG hydrogel facilitated the in-situ synthesis of PEDOT within the hydrogel, producing a hydrogel with a higher conductivity, which was further enhanced by H2SO4 treatment. The resultant semi-interpenetrating network hydrogel scaffolds were shown to consist of up to more than 80wt% of water with a compressive modulus of 21kPa and an electrical conductivity of 1.69×10−2 Scm−1. The surface of the resultant conductive hydrogel could be modified via photochemical fixation for cell adhesion with negligible conductivity change. In vitro studies using electro-responsive H9C2 myocytes showed that the developed hydrogels not only did not exhibit any cytotoxicity but also supported cell adhesion and proliferation. This work demonstrates that the architectural design of the conductive hydrogel scaffolds and growth mechanism of PEDOT in the hydrogel platform play a pivotal role in determining the properties of the resulting conductive hydrogel. The attractive performance of these hybrid hydrogels will open a new approach for the further research on electrically conductive tissue engineering scaffolds.

      PubDate: 2016-10-02T04:32:45Z
      DOI: 10.1016/j.reactfunctpolym.2016.09.003
      Issue No: Vol. 109 (2016)
       
  • Hydroxyl-enhanced magnetic chitosan microbeads for boron adsorption:
           Parameter optimization and selectivity in saline water
    • Authors: Akeem Adeyemi Oladipo; Mustafa Gazi
      Pages: 23 - 32
      Abstract: Publication date: Available online 29 September 2016
      Source:Reactive and Functional Polymers
      Author(s): Akeem Adeyemi Oladipo, Mustafa Gazi
      Hydroxyl-enhanced materials are considered promising for boron adsorption. But, the use of these materials is hindered by issues of selectivity and separation notably in the presence of co-existing ions. Therefore, magnetic chitosan-based microbeads (MC) were synthesized and functionalized with a glycidol to produce boron-selective adsorbent (MCG). The resulting multi-hydroxyl microbeads were found to be a better substitute to the existing boron adsorbents. The adsorbents were characterized by scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The BET surface area and vibrating sample magnetometry analyzes confirmed that the functionalized beads had a saturation magnetization, surface area, pore size, and diameter of 46.53Am2/kg, 598m2/g, 2.9nm and ∼150–400μm respectively. Under optimized condition, the MCG showed high adsorption affinity and remarkable selectivity towards boron in the presence of co-existing metal ions (Cu2+, Fe3+, and Ni2+) and salts of Mg2+, Ca2+, Na+ and K+ ions. MCG has 128.5mg/g of boron loading capacity within the first 100min, which is relatively higher than reported values. The spent beads were separated easily from the suspensions by an external magnet and reuse repeatedly.

      PubDate: 2016-10-02T04:32:45Z
      DOI: 10.1016/j.reactfunctpolym.2016.09.005
      Issue No: Vol. 109 (2016)
       
  • Synthesis of novel monolithic cartridges with specific recognition sites
           for extraction of melamine
    • Authors: Evin Mine Dursun; Recep Üzek; Nilay Bereli; Serap Şenel; Adil Denizli
      Pages: 33 - 41
      Abstract: Publication date: Available online 23 September 2016
      Source:Reactive and Functional Polymers
      Author(s): Evin Mine Dursun, Recep Üzek, Nilay Bereli, Serap Şenel, Adil Denizli
      Synthesis of melamine (ME) imprinted polymeric sorbent for use as solid phase extraction adsorbent was targeted and the benefits of the synthesis in the monolith format were combined with imprinting technology advantages. Melamine as template and 2-vinylimidazole-Cu2+ as complexing agent were used as the first time for pre-complex formation, followed by the preparation of monolith by bulk polymerization method in the presence of ethyleneglycol dimethacrylate as crosslinker, azobisisobutyronitrile as initiator, and ethyl alcohol as solvent for a duration of 4h at 80°C. 1.0M NaOH solution was used as a desorption agent to remove template. Non-imprinted monolith (NIP) were synthesized as a control without template in same receipt. The monolith samples were characterized by Fourier Transformed Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), elementary analysis, and Branauer- Emmett- Teller (BET) studies. Melamine adsorption from aqueous solution was studied in continuous mode, and some parameters such as pH, temperature, concentration and flow-rate were optimized for melamine adsorption. The maximum adsorption capacities were determined as 147.9mg/g for imprinted polymer (MIP), 82.0mg/g for non-imprinted polymer (NIP) and 4.0mg/g for polymer without pre-complex (E) at 25°C, and pH5.0 with 500ppm melamine initial concentration for 1.0mL/min flow-rate. In addition to interaction characterized by metal coordination bond formation, non- covalent interactions were responsible for melamine adsorption. No significant change in adsorption performance was recorded after 10 consecutive adsorption-desorption cycles. Kinetic analysis indicated compliance with pseudo-second order kinetics. The Freundlich isotherm was found suitable for description of the process. Cyanuric acid (CY), aniline (AN), and phenol (PH) were used as competing agents in selectivity studies, and relative selectivity coefficients were calculated (k'CY =4.45; k'AN =7.08; k'PH =3.98). The performance of melamine imprinted polymeric monolith (MIP) as solid-phase extraction adsorbent for extraction of melamine from milk samples was investigated and the recovery of melamine in spiked milk samples was 97.6% with the relative standard deviation (RSD) (8.1%).

      PubDate: 2016-09-26T04:08:54Z
      DOI: 10.1016/j.reactfunctpolym.2016.09.002
      Issue No: Vol. 109 (2016)
       
  • Preparation and fracture process of high strength hyaluronic acid
           hydrogels cross-linked by ethylene glycol diglycidyl ether
    • Authors: Burak Tavsanli; Oguz Okay
      Pages: 42 - 51
      Abstract: Publication date: Available online 6 October 2016
      Source:Reactive and Functional Polymers
      Author(s): Burak Tavsanli, Oguz Okay
      We present a synthetic strategy to produce high-strength hydrogels based on hyaluronic acid, a unique biomacromolecule with distinctive biological functions. The hydrogels were prepared using a two-step procedure. In the first step, hyaluronic acid (HA) was chemically cross-linked in aqueous solutions using ethylene glycol diglycidyl ether (EGDE) under various experimental conditions. EGDE-cross-linked HA hydrogels containing 97–99% water were fragile, and ruptured when compressed to 25–51% strain under 0.02–0.15MPa stresses. By applying the double-network approach in the second step, we were able to generate high strength HA/ poly(N,N-dimethylacrylamide) double-network hydrogels containing 84–94% water. Tuning the ratio of the network components could result in hydrogels exhibiting a compressive modulus of 0.9MPa that sustain 19.4MPa compressive stresses, which are much larger than those reported before for the hydrogels derived from the methacrylated HA macromers. Thus, the hydrogels presented here are promising materials to make use the characteristics of HA in stress-bearing biomedical applications. Cyclic mechanical tests show irreversible stress-strain curves with a large hysteresis indicating that elastically effective cross-links of HA first-network are irreversibly destroyed under load by dissipating energy. This internal fracture of HA network together with the high mass ratio of the second to the first-network components are responsible for the extraordinary mechanical properties of the hydrogels.

      PubDate: 2016-10-09T23:03:17Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.001
      Issue No: Vol. 109 (2016)
       
  • Highly branched polyethylenes as lubricant viscosity and friction
           modifiers
    • Authors: Joshua W. Robinson; Yan Zhou; Jun Qu; J. Timothy Bays; Lelia Cosimbescu
      Pages: 52 - 55
      Abstract: Publication date: Available online 8 October 2016
      Source:Reactive and Functional Polymers
      Author(s): Joshua W. Robinson, Yan Zhou, Jun Qu, J. Timothy Bays, Lelia Cosimbescu
      A series of highly branched polyethylenes (BPE) were prepared and evaluated in a Group I base oil as potential viscosity and friction modifiers. The performance of these BPEs supports the expected dual functionality. Changes in polarity, topology, and molecular weight of the BPEs showed significant effects on the lubricants' performance with respect to viscosity index and friction reduction. This study provides scientific insights into polymer design for future lubricant development activities.

      PubDate: 2016-10-09T23:03:17Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.003
      Issue No: Vol. 109 (2016)
       
  • The preparation and study of poly(vinylidene
           fluoride)/ultrahigh-molecular-weight polyethylene/SiO2 hollow fiber
           membrane with network enhanced structure
    • Authors: Nana Li; Feng Liu; Qingchen Lu; Yanli Shi; Changfa Xiao; Bowen Cheng
      Pages: 64 - 69
      Abstract: Publication date: December 2016
      Source:Reactive and Functional Polymers, Volume 109
      Author(s): Nana Li, Feng Liu, Qingchen Lu, Yanli Shi, Changfa Xiao, Bowen Cheng
      The compatibility of poly(vinylidene fluoride) (PVDF)/ultrahigh-molecular-weight polyethylene (UHMWPE) blends is studied by methods of solubility parameter and melting temperature decreasing. And the melting behavior and crystallization properties are researched by rheological properties testing and differential scanning calorimetry. Based on these, PVDF/UHMWPE/SiO2 blends hollow fiber hydrophobic membranes with network enhanced structure and porous structure are prepared by thermally induced phase separation (TIPS) and screw extrusion spinning method, with mineral oil as diluent. Then the membrane morphology is observed by scanning electron microscopy (SEM). Finally, properties of membrane are studied by porosity and pore diameter analysis, stretching experiment and contact angle measurement. The results show that the porous structure is improved by interface pores formed due to the poor compatibility between PVDF and UHMWPE. Moreover, the network enhanced structure with rough surface is built by PVDF spherical micro-particles and SiO2 inorganic particles connected with UHMWPE micro-fibrils. The structure can strengthen mechanical properties of membrane.

      PubDate: 2016-10-30T21:45:44Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.005
      Issue No: Vol. 109 (2016)
       
  • Preparation of multifunctional conductive polymers with-C=N-conjugated
           system and amino groups and application as active coating additives
    • Authors: Xiaodong Quan; Jixiao Wang; Song Zhao; Zhi Wang; Shichang Wang
      Pages: 79 - 87
      Abstract: Publication date: December 2016
      Source:Reactive and Functional Polymers, Volume 109
      Author(s): Xiaodong Quan, Jixiao Wang, Song Zhao, Zhi Wang, Shichang Wang
      Multifunctional conductive polymers with CN conjugated system and functional groups were prepared by polycondensation of carbamide at high temperature under elevated pressure. The corresponding molecular structures of these polycondensation of carbamide products (PCA) were proposed according to the analysis of elemental analysis, FT-IR spectra, UV–Visible absorption spectra and X-ray photoelectron spectroscopy. The morphology of the obtained products can be tuned by controlling the synthesis conditions such as temperature, pressure and catalyst used in the synthesis process. X-ray diffraction (XRD) patterns confirmed the existence of relatively ordered crystal structures for these polymers. Corrosion protection performance of as-prepared coatings with PCAs was investigated based on NaCl solution immersion test. The results indicated that PCA-2 nanoparticles can improve the protection performance for metals by increasing the adhesion strength of the epoxy coatings and acting as crosslinking points to form a dense film.

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.014
      Issue No: Vol. 109 (2016)
       
  • Editorial
    • Authors: Guey-Sheng Liou; Wen-Chang Chen; Toyoji Kakuchi
      First page: 1
      Abstract: Publication date: November 2016
      Source:Reactive and Functional Polymers, Volume 108
      Author(s): Guey-Sheng Liou, Wen-Chang Chen, Toyoji Kakuchi


      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.006
      Issue No: Vol. 108 (2016)
       
  • Highly transparent polyimide hybrids for optoelectronic applications
    • Authors: Chia-Liang Tsai; Hung-Ju Yen; Guey-Sheng Liou
      Pages: 2 - 30
      Abstract: Publication date: November 2016
      Source:Reactive and Functional Polymers, Volume 108
      Author(s): Chia-Liang Tsai, Hung-Ju Yen, Guey-Sheng Liou
      Polyimides comprising high polarized moieties and electron-withdrawing groups usually exhibit high refractive index and good transparency with great potential for optoelectronic devices. Particularly, the incorporation of hydroxyl groups on the backbones of polyimides is an important strategy to enhance the solubility and provide reactive sites for organic-inorganic bonding. Composites prepared from organic polymer binder and inorganic fillers have recently attracted considerable interests due to their enhanced mechanical, thermal, optical and electrical properties compared to the corresponding polymer or inorganic component. Moreover, the inorganic components in hybrid films can also serve as electron acceptors for stabilizing the charge transfer complex thus result in electrically programmable digital memory properties. In addition, the high performance polyimides can further served as substrate and protector for the AgNWs-polyimide conductive hybrid films, exhibiting good adhesive property, high bendability, and excellent thermal stability. Owing to the high glass transition temperature (T g) of polyimides, the resulted AgNWs-polyimide electrode can maintain its conducting performance at high temperature operation. Thus, the hybrid electrode provided extremely high potential to operate at harsh working environment or further post processing. By the excellent combination of transparent polyimides and inorganic materials, the resulting polyimide hybrids showing promising potential are indispensable to optical and electrical applications.

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.04.021
      Issue No: Vol. 108 (2016)
       
  • Progress on nanocrystalline cellulose biocomposites
    • Authors: Nurhidayatullaili Muhd Julkapli; Samira Bagheri
      Abstract: Publication date: Available online 21 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Nurhidayatullaili Muhd Julkapli, Samira Bagheri
      Nanocrystalline cellulose (NCC) a rigid rod-like nanoscale material, can be produced from cellulosic biomass including wood and non-wood based materials in powder, liquid or gel form by acid and chemical hydrolysis. Owing to its unique and exceptional renewability, biodegradability, mechanical, physicochemical properties and characteristics of abundance, the incorporation of a small amount of NCC to the materials matrix (polymer, ceramic and/or metal) enhances the mechanical strength of the latter by several orders of magnitudes. Besides, NCC as a material derived from natural sources has no serious environmental concerns, providing further impetus for the development and applications of this green and renewable biomaterial to fabricate lightweight and biodegradable composites. Surface functionalization of NCC remains the main focus of NCC research to tailor its properties for dispersion in hydrophilic and hydrophobic media. It is of uttermost importance to develop tools and protocols for imaging of NCC in a complex matrix and quantify its reinforcement, antimicrobial, stability, hydrophilicity and biodegradability effect. This review highlights NCC biocomposites, preparation, modification, and potential applications.

      PubDate: 2016-12-27T10:16:11Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.013
       
  • Versatile synthesis of comb-shaped poly(lactic acid) copolymers with
           poly(acrylic acid)-based backbones and carboxylic acid end groups
    • Authors: Pavel Kucharczyk; Jiri Zednik; Petr Humpolicek; Zdenka Capakova; Vladimir Sedlarik
      Abstract: Publication date: Available online 21 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Pavel Kucharczyk, Jiri Zednik, Petr Humpolicek, Zdenka Capakova, Vladimir Sedlarik
      This paper focuses on preparing and characterizing nonlinear, highly carboxylic-functionalized poly(lactic acid) copolymer prepared through a reaction between poly(acrylic acid) and lactic acid. The resultant copolymer exhibits a comb architecture, in which poly(acrylic) acid creates the backbone and poly(lactic acid) its side arms. Thorough analysis was conducted on the molecular weight of polymers by gel permeation chromatography through triple detection of light-scattering and viscometry. Each copolymer property was studied in detail. Finally, cytotoxicity assay was also performed. Results showed that comb and multi-comb macromolecular architectures co-existed in the sample and that their size and amount are easily tuneable by ratio of the initial reactant.

      PubDate: 2016-12-27T10:16:11Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.012
       
  • Miscibility of polyimide blends: Physicochemical characterization of two
           high performance polyimide polymers
    • Authors: Saeed Mazinani; Siavash Darvishmanesh; Rouzbeh Ramezani; Bart Van der Bruggen
      Abstract: Publication date: Available online 16 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Saeed Mazinani, Siavash Darvishmanesh, Rouzbeh Ramezani, Bart Van der Bruggen
      The intermolecular interactions and miscibility behavior of two polyimide blend systems, Extem/Matrimid and Extem/U-Varnish, in compositions of 100/0, 80/20, 50/50, 20/80, 0/100 have been evaluated. The polymer blend systems have been characterized by different analytical techniques such as optical microscopy, Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and rheological measurements. DSC results for the Extem/U-Varnish system showed the existence of a single glass transition temperature (Tg) in each composition, suggesting the miscibility of the blends, whereas DSC analysis of Extem/Matrimid system indicated immiscibility but compatibility between two polymers. In order to study the specific interactions between Extem and U-Varnish polymers, the Tgs of the polymer blends were estimated by theoretical equations and compared with experimental data. The empirical Tg values formed a concave curve as a function of composition and exhibited a positive deviation from the linearity, indicating the presence of specific interactions between Extem and U-Varnish polymer chains; this was confirmed by FTIR spectra. Interactions between studied polymer systems and four aprotic solvents including N-methyl-2-pyrrolidone (NMP), Dimethylacetamide (DMAc), Dimethylformamide (DMF) and Dimethyl sulfoxide (DMSO) were assessed on the basis of the difference between their solubility parameters. Among the selected solvents, DMAc showed the highest affinity with both blend systems. XRD patterns and rheological behavior of Extem/U-Varnish system revealed that the crystalline nature and viscosity of the blend polymers decreases as the ratio of Extem/U-Varnish increases. As an overall conclusion, Extem and U-Varnish were found to constitute a miscible pair at a molecular level over the entire composition range whereas Extem and Matrimid could not form a miscible blend.

      PubDate: 2016-12-19T09:00:32Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.010
       
  • A methacryl ethyl-functionalized soluble polypyrrole: Synthesis,
           characterization, and potentiality in rapid fabrication of
           high-aspect-ratio pillar arrays
    • Authors: Guowei Lv; Shihu Zhang; Guolong Wang; Jinyou Shao; Hongmiao Tian; Demei Yu
      Abstract: Publication date: Available online 6 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Guowei Lv, Shihu Zhang, Guolong Wang, Jinyou Shao, Hongmiao Tian, Demei Yu
      A methacryl ethyl-functionalized soluble polypyrrole was designed and prepared by chemical oxidative polymerization for rapid fabrication of high-aspect-ratio pillar arrays. The chemical structures of the pyrrole derivative and the corresponding polypyrrole were characterized by FTIR and 1H NMR. The polypyrrole with a weight-average molecular weight (Mw) of 7376 exhibits good solubility in several organic solvents, favorable thin film-forming ability and two UV–Vis absorption peaks at 280 and 380nm in tetrahydrofuran solution. The dilute chloroform solution of the polypyrrole is a Newtonian fluid with a low viscosity and shows a significant increase in the electrical conductivity with increasing the polypyrrole content. Moreover, an insulating photoresist can be transformed into a conductive photoresist by doping this polypyrrole. Electrowetting driven structure formation experiments have confirmed that the conductive photoresist can fulfill rapid fabrication of higher-aspect-ratio pillar arrays compared with the insulating photoresist.
      Graphical abstract image

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.005
       
  • Novel iodo-containing poly(arylene ether ketone)s as intermediates for
           grafting perfluoroalkyl sulfonic acid groups
    • Authors: Siyuan Liu; Wu Luo; Hanyu Zhang; Xiaobai Li; Wei Hu; Michael D. Guiver; Baijun Liu
      Abstract: Publication date: Available online 6 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Siyuan Liu, Wu Luo, Hanyu Zhang, Xiaobai Li, Wei Hu, Michael D. Guiver, Baijun Liu
      A synthetic approach to poly(arylene ether ketones) grafted with super-acidic perfluoroalkyl-sulfonic-acids is reported. A series of iodo-containing poly(arylene ether ketone)s derived from a 4-iodophenylated hydroquinone monomer were synthesized by aromatic nucleophilic substitution (SNAr). The iodo-containing polymers were functionalized via the Ullmann reaction to give poly(arylene ether ketone)s grafted with perfluoroalkyl-sulfonic-acid. The perfluoroalkyl-sulfonic-acid functionalized aromatic polymers were investigated as proton exchange membranes (PEM). The membranes had good overall properties of thermal-oxidative stability, mechanical strength, methanol permeability and proton conductivity. A membrane with IEC ~1.37meqg−1 had a proton conductivity of 0.088Scm−1 at 100°C, which was higher than many sulfonated hydrocarbon PEMs with similar IEC values.

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.002
       
  • Preparation and properties of quaternary ammonium chitosan-g-poly(acrylic
           acid-co-acrylamide) superabsorbent hydrogels
    • Authors: Guanghua He; Wanwan Ke; Xiang Chen; Yahui Kong; Hua Zheng; Yihua Yin; Weiquan Cai
      Abstract: Publication date: Available online 6 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Guanghua He, Wanwan Ke, Xiang Chen, Yahui Kong, Hua Zheng, Yihua Yin, Weiquan Cai
      Quaternary ammonium chitosan-g-poly(acrylic acid-co-acrylamide) superabsorbent hydrogels were successfully synthesized from acrylic acid (AA), acrylamide (AM) and quaternary ammonium chitosan with high substitution degree. They were prepared using potassium persulfate (KPS) as an initiator and N,N′-methylenebisacrylamide (MBA) as a crosslinker respectively. The structure and morphology of the superabsorbent hydrogel were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The water absorbency and antibacterial activities of the superabsorbent hydrogels against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated. The introduction of quaternary ammonium chitosan made the antibacterial activity improved. The crosslinker, initiator and AM contents had certain influences on the water absorbency as well as the antibacterial activity against E. coli. The AM could enhance the hydrogel strength apparently. In addition, the AM (the content was 10wt%) could increase the water absorbency in 0.9wt% NaCl solution obviously. The superabsorbent hydrogel also had pH sensitive property.

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.001
       
  • Low molecular chitosan–(poly)nitroxides: Synthesis and evaluation as
           antioxidants on free radical-induced erythrocyte hemolysis
    • Authors: Vasily D. Sen; Ekaterina M. Sokolova; Nikolai I. Neshev; Alexander V. Kulikov; Evgeny M. Pliss
      Abstract: Publication date: Available online 7 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Vasily D. Sen, Ekaterina M. Sokolova, Nikolai I. Neshev, Alexander V. Kulikov, Evgeny M. Pliss
      Water-soluble chitosan-(poly)nitroxides (CPNs), differing in molecular weight of the saccharide backbone and the nature of nitroxide radical, were obtained and characterized. Fractions of modified glucosamines were in the range 0.15–0.28. The dependence of delay time of 2,2-azobis-2-methylpropanimidamide dihydrochloride (AAPH)-induced erythrocyte hemolysis on the concentration of CPNs and data of electron paramagnetic resonance (EPR) spectra indicate their binding to the cell membrane. Because of this binding, CPNs demonstrate identical delay times of hemolysis at concentrations ~100 times lower than structurally similar low molecular nitroxides. Due to easier oxidation of piperidine nitroxide by radicals RO2 to oxoammonium cations, CPNs with attached 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) more effectively inhibit hemolysis than their counterparts with 2,2,5,5-tetramethylpyrroline-1-oxyl. Recycling of nitroxides, presumably, take place through the reaction of oxoammonium cations with common biological reductants. Taken together, our study suggests that CPNs are of interest both as biologically active compounds and as research instruments.

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.006
       
  • Selenide-containing high refractive index polymer material with adjustable
           refractive index and Abbe's number
    • Authors: Huinan Jiang; Xiangqiang Pan; Na Li; Zhengbiao Zhang; Jian Zhu; Xiulin Zhu
      Abstract: Publication date: Available online 8 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Huinan Jiang, Xiangqiang Pan, Na Li, Zhengbiao Zhang, Jian Zhu, Xiulin Zhu
      Poly(glycidyl methacrylate) (PGMA) was synthesized by Fe(0)-mediated living radical polymerization followed with post-modification by PhSeZnCl. A series of selenide functionalized PGMAs with different selenium concentrations and molecular weights were obtained. The introduction of selenide groups into PGMA resulted in a polymer with high refractive index. The relationships between the concentration of selenium, degree of polymerization and refractive index were investigated. Results showed that the refractive index of the final polymer could be adjusted by the concentration of selenium and degree of polymerization, which provided a useful way to fabricate polymeric materials with adjustable refractive index.

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.007
       
  • Dual thermo/oxidation-responsive block copolymers with self-assembly
           behaviour and synergistic release
    • Authors: Meiqiong Tang; Qiang Zheng; Nicola Tirelli; Ping Hu; Qing Tang; Jin Gu; Yun He
      Abstract: Publication date: Available online 8 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Meiqiong Tang, Qiang Zheng, Nicola Tirelli, Ping Hu, Qing Tang, Jin Gu, Yun He
      The synthesis of novel amphiphilic poly(propylene sulfide) (PPS) and poly(N-isopropylacrylamide) (PNIPAm) block copolymers is reported as a strategy to respond stimuli in inflammatory tissues. In addition to the formation of defined PPS-block-PNIPAm assemblies, the encapsulation of fluorescent dyes and the selective response to the heat and oxidants are studied. The synthesis of the dual responsive PPS-b-PNIPAm is carried out by combining a living anionic ring-opening and an atom transfer radical polymerization (ATRP) process. The resulting copolymers are self-assembled in water to form aggregated structures, which are characterized by dynamic light scattering (DLS) and scanning electronic microscopy (SEM). DLS measurements show that heat and oxidants cause a significant change to the hydrodynamic diameter of the particles. Fluorescent spectroscopy data confirms the liberation of the encapsulated dye, which indicates the decomposition of the particles and validates the concept of stimuli-triggered payload release. Finally, cytotoxicity assays confirm that the PPS-b-PNIPAm copolymer is biocompatible with A549 lung cancer cells.

      PubDate: 2016-12-11T10:58:23Z
      DOI: 10.1016/j.reactfunctpolym.2016.12.009
       
  • Maleic anhydride functionalization of OSTE based coatings via thiol-ene
           “Click” reaction for the covalent immobilization of xylanase
    • Authors: Emrah Çakmakçi; Başak Yuce-Dursun; Serap Demir
      Abstract: Publication date: Available online 3 December 2016
      Source:Reactive and Functional Polymers
      Author(s): Emrah Çakmakçi, Başak Yuce-Dursun, Serap Demir
      Combination of Off-Stoichiometry Thiol-Ene (OSTE) polymers with thiol-ene “Click” reaction is a versatile method for the development of advanced functional materials. In this study OSTE based photocurable coating materials with excess thiol groups on the surface were prepared and functionalized with maleic anhydride via thiol-ene “Click” reaction. Xylanase enzyme was then covalently immobilized onto these coatings. Maleic anhydride functionalization of the prepared OSTE coatings was proved by FTIR and contact angle measurements. The developed functional support was found to have high affinity for xylanase enzyme and the immobilization capacity was determined as 212mgg−1. Almost 100% of immobilization yield was achieved. Immobilization significantly improved the stability of the xylanase at pH values over 6.5 and temperatures exceeding 60°C. Moreover the immobilized xylanase exhibited superior reusability and storage stability compared to free xylanase.

      PubDate: 2016-12-05T12:32:29Z
      DOI: 10.1016/j.reactfunctpolym.2016.11.006
       
  • Novel phenolic antioxidant-functionalized dendritic polyethylene:
           Synthesis by tailor-made nickel(II) α-diimine-catalyzed copolymerization
           and its characteristics as non-releasing additive
    • Authors: Zahra Balzadeh; Hassan Arabi
      Abstract: Publication date: Available online 25 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Zahra Balzadeh, Hassan Arabi
      This work describes a simple one-pot and controlled synthetic method to generate migration-resistant bio-friendly tailor-made antioxidants through dendritic polyethylene (DPE)–sterically hindered phenolic antioxidant (SHPA) copolymerization by coordination polymerization using MAO-activated nickel(II)-α-diimine catalyst. The antioxidant tethering into the polymer chain by chain walking catalysts leads to adjustable copolymer architectures possessing different thermal features. It was found that oxidation induction time could be fine-tuned (from 2 to 36min) by appropriate SHPA content selection and PE altering (from 10 to 0.5bar of gage). Furthermore, the chemical composition analysis of DPE–SHPA copolymer shows 0.6wt% SHPA incorporation (approximately 80% conversion) besides a dendritic architecture, containing 123 branches per 1000 carbon atoms and AFM images resembling semi-spherical topology. The migration resistance of the synthesized copolymers and their application as non-releasing additives are also investigated.

      PubDate: 2016-11-27T14:45:28Z
      DOI: 10.1016/j.reactfunctpolym.2016.11.005
       
  • Effect of reactive functionalization on properties and degradability of
           poly(lactic acid)/poly(vinyl acetate) nanocomposites with cellulose
           nanocrystals
    • Authors: Minhaz-Ul Haque; Debora Puglia Elena Fortunati Mariano Pracella
      Abstract: Publication date: Available online 15 November 2016
      Source:Reactive and Functional Polymers
      Author(s): M. Minhaz-Ul Haque, Debora Puglia, Elena Fortunati, Mariano Pracella
      Nanocomposites of poly(lactic acid) (PLA) containing cellulose nanocrystals (CNCs) were prepared by dispersion of CNCs in aqueous poly(vinyl acetate) (PVAc) emulsion followed by melt extrusion with PLA. Functionalization of PVAc by radical grafting of glycidyl methacrylate (PVAc-GMA) was carried out during PVAc polymerization by using ammonium cerium (IV) nitrate as the initiator. The morphology, phase interactions, thermal and mechanical properties and degradability in composting of blends (PLA/PVAc, PLA/PVAc-GMA) and nanocomposites (PLA/PVAc/CNC, PLA/PVAc-GMA/CNC) containing 3wt% CNC were examined by FESEM, AFM, FT-IR, DSC and tensile tests. The study of degradability demonstrated that the disintegration rate of PLA/PVAc-GMA/CNC in soil was higher than that of PLA/PVAc/CNC, likely because the epoxy groups of GMA accelerated the biodegradation rate through the formation of radicals.
      Graphical abstract image

      PubDate: 2016-11-21T03:11:01Z
       
  • Amphiphilic block-random copolymer surfactants with tunable
           hydrophilic/hydrophobic balance for preparation of non-aqueous dispersions
           by an emulsion solvent evaporation method
    • Authors: Naofumi Ezaki; Yoshifumi Watanabe Hideharu Mori
      Abstract: Publication date: Available online 16 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Naofumi Ezaki, Yoshifumi Watanabe, Hideharu Mori
      The structural effects of amphiphilic block-random copolymers composed of stearyl methacrylate (SMA) and diethanolamine-modified glycidyl methacrylate (DEAGMA), poly(SMA)-b-poly(DEAGMA-r-SMA)s on their surfactant efficacy for a non-aqueous emulsion solvent evaporation method were investigated. Three series of block-random copolymers (i) with different amounts of DEAGMA in the poly(DEAGMA-r-SMA) segment and (ii, iii) with different chain lengths of each segment were synthesized by reversible addition-fragmentation chain transfer polymerization. The surfactant efficacies of these copolymers were investigated in terms of the interfacial tension and modulus, size, and stability of the emulsion and dispersion. Suitable comonomer composition and chain lengths of both segments produced stable emulsions and dispersions with small particle sizes (<200nm).

      PubDate: 2016-11-21T03:11:01Z
       
  • Synthesis and adsorptive characteristics of novel chitosan/graphene oxide
           nanocomposite for dye uptake
    • Authors: Muhammad Arif; Kamal Saira Bibi Syeda Wishal Bokhari Ahmad Hassan
      Abstract: Publication date: Available online 16 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Muhammad Arif Kamal, Saira Bibi, Syeda Wishal Bokhari, Ahmad Hassan Siddique, Tariq Yasin
      A green approach was utilized to synthesize crosslinked chitosan-based graphene oxide (GO) nanocomposite membrane using tetraethyl orthosilicate (TEOS) as a crosslinking agent. The structural analysis of the membranes was investigated using infrared (IR) spectroscopy. The porosity and morphology of membranes were examined using scanning electron microscopy (SEM) and BET (Brunauer–Emmett–Teller) techniques. The SEM micrographs revealed that GO was uniformly mixed in chitosan matrix. BET results further confirmed that the inclusion of GO led to increase the surface area of the nanocomposite which also improved its adsorptive properties. Congo red (CR) dye was used to study the adsorption efficiency of developed membrane. The effect of time, pH and dose rate on the adsorption behavior of developed membrane was investigated. The maximum loading capacity of CR on CS/GO membrane was 175.9mg/g. The kinetics and equilibrium isotherms were well described by pseudo-second-order and Langmuir isotherm models respectively. The high adsorption efficacy and green nature of the nanocomposites provide a good alternative to already existing petroleum based (biostable) membranes.

      PubDate: 2016-11-21T03:11:01Z
       
  • Pb2+ removal from aqueous synthetic solutions by calcium alginate and
           chitosan coated calcium alginate
    • Authors: Noor Edin Mousa; Claudia Maria Simonescu; Rodica-Elena Pătescu; Cristian Onose; Christu Tardei; Daniela C. Culiţă; Ovidiu Oprea; Delia Patroi; Vasile Lavric
      Abstract: Publication date: Available online 10 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Noor Edin Mousa, Claudia Maria Simonescu, Rodica-Elena Pătescu, Cristian Onose, Christu Tardei, Daniela C. Culiţă, Ovidiu Oprea, Delia Patroi, Vasile Lavric
      This research study deals with lead(II)/Pb2+ removal from aqueous solutions by calcium alginate (CA) and chitosan coated calcium alginate (CCCA) as adsorbents, in batch experiments. A simple synthesis method was used to prepare both adsorbent materials. CA and CCCA were characterized using infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetric analysis (TG). The main parameters determining the quantity of lead(II) ions adsorbed are: the initial pH solution, the lead(II)ions initial concentration and the temperature. The experiments revealed that the adsorption capacity, thus, the removal efficiency are higher for CCCA compared to CA. The adsorption of lead(II) ions onto both CA and CCCA materials is an endothermic spontaneous process, as resulted from the thermodynamic experiments. Consequently, a moderate increase of temperature improves the adsorption capacity. The thermodynamic equilibrium sorption experimental data are well fitted by Freundlich adsorption isotherm for both tested adsorbents, better than Langmuir's. Accordingly, lead(II) ions adsorption onto CA and CCCA develops obeying a multilayer mechanism. The kinetic experimental data were fitted by both pseudo-first, and pseudo-second order models. The former approaches better the experimental results for both adsorbents. The mechanism involved in lead removal is a combination between ion-exchange and coordination/chelation based on experimental results.

      PubDate: 2016-11-14T02:52:37Z
      DOI: 10.1016/j.reactfunctpolym.2016.11.001
       
  • Synthesis of curcumin/polyrhodanine nanocapsules with antimicrobial
           properties by oxidative polymerization using the Fenton reaction
    • Authors: Jun-Won Kook; Soyeon Kim; Jun-Young Lee; Jung-Hyun Kim
      Abstract: Publication date: Available online 3 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Jun-Won Kook, Soyeon Kim, Jun-Young Lee, Jung-Hyun Kim
      Curcumin exhibits various biological activities; however, its applications are limited because of its poor water solubility. In this study, we describe an encapsulation process that improves this property using a polyrhodanine shell material synthesized by oxidative polymerization. Unlike the previous methods of oxidative polymerizations, we used the Fenton reaction to introduce a FeCl3/H2O2 combination system. By changing the rhodanine monomer ratio, the curcumin/polyrhodanine nanocapsule (CPR-NC) shell thickness could be controlled. The release behavior of curcumin was characterized by UV–Vis spectroscopy over time. Antimicrobial tests with curcumin, polyrhodanine, and CPR-NC were performed to analyze the minimum inhibitory concentration and inhibition zones.

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.016
       
  • Surface molecularly imprinted organic-inorganic polymers having affinity
           sites for cholesterol
    • Authors: Irina Polyakova; Ludmila Borovikova; Aleksandra Osipenko; Elena Vlasova; Boris Volchek; Oleg Pisarev
      Abstract: Publication date: Available online 3 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Irina Polyakova, Ludmila Borovikova, Aleksandra Osipenko, Elena Vlasova, Boris Volchek, Oleg Pisarev
      Novel granular organic-inorganic molecularly imprinted polymers (MIPs) based on 2-hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA) were prepared by co-polymerization on the surface of selenium (Se) nanoparticles stabilized with poly(vinyl pyrrolidone) (PVP) at different concentrations of cholesterol as a template molecule. The synthesis occurred in Pickering microemulsion. The obtained compounds are intended for use as selective hemosorbents in efferent therapy of hypercholesterolemia. The sorbents were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and sorption experiments. It was revealed that MIPs possess more pronounced porous structure as compared to that of the reference non-imprinted polymer (NIP). The influence of the amount of introduced cholesterol template on physico-chemical and sorption properties of MIPs was investigated. FTIR spectroscopy and thermodynamic studies showed that the affinity of MIPs towards cholesterol is related to multi-point polyfunctional binding of adsorbate in complementary cavities or imprint sites; hydrogen bonds play the key role in recognition of the target molecule. The Langmuir, Freundlich, Temkin and BET model isotherms were used for interpreting the experimental data on the equilibrium sorption experiments. The maximum adsorption capacities increased for the MIP synthesized at the highest molar concentration of the template. Cholesterol adsorption proceeded in the monolayer within a wide concentration range, and the data obtained in these experiments better conformed to the Langmuir isotherm. Formation of the surface sorption layer in the MIPs facilitates availability of imprint sites and enhances the efficiency of specific cholesterol binding from blood plasma in vitro.

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.010
       
  • Synthesis and chiroptical properties of novel helical polyacetylenes
           containing fluorene pendant groups in the side chains
    • Authors: Yuping Liu; Shujing Li; Qingzhong Zhang; Jing Zhang; Chunping Du; Wei Huang
      Abstract: Publication date: Available online 2 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Yuping Liu, Shujing Li, Qingzhong Zhang, Jing Zhang, Chunping Du, Wei Huang
      A series of novel substituted acetylene monomers bearing fluorene pendant groups (C13H9COCH2CH2CO-R-CH2C≡CH, R=NH (IV 1 ), R=O (IV 2 ), R=NHCH(CH3)CONH (IV 3 ), R=NHCH(CH3)COO (IV 4 )) have been synthesized and subsequently polymerized with [Rh(nbd)Cl]2 as a catalyst to obtain the corresponding polyacetylenes (Poly(IV 1–4 )). The 1H NMR spectra demonstrated that all the obtained polyacetylenes had high cis-stereoregular structures. The results of CD (circular dichroism) and UV–vis spectra showed that Poly(IV 3,4 ) took a tight helical structure, while Poly(IV 1,2 ) did not. The chiral amino acid units in the side chains of Poly(IV 3,4 ) induced the main chain to form the helical conformation. In addition, owing to the large steric repulsion and π-π interaction between the bulky fluorene groups, Poly(IV 3,4 ) showed good helical stability at various temperatures (−10–60°C) and in strong polar solvents. Especially, the CD intensity of Poly(IV 3 ) was enhanced with increasing the solvent polarity. Moreover, Poly(IV 1–4 ) also showed good photoluminescent (PL) properties. The nonconjugated aliphatic spacer and the twisting of the polymer main chain were favorable to improve the PL efficiency.

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.015
       
  • Au (III) Uptake by Triazine Polyamine Polymers: Mechanism, Kinetic and
           Equilibrium Studies
    • Authors: Mustafa Can; Melek Doğan; Mustafa İmamoğlu; Mustafa Arslan
      Abstract: Publication date: Available online 3 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Mustafa Can, Melek Doğan, Mustafa İmamoğlu, Mustafa Arslan
      Triazine-polyamine polymers were successfully synthesized and adsorption of the gold (III) ions from chloride-containing solutions was carried out by comparing the effect of amine chain lengths in the polymers triazine-ethylenediamine (EDA), triazine-triethylenetetramine (TETA) and triazine-pentaethylene hexamine (PEHA). The second-order kinetic equation provides the best correlation for the adsorption process. Langmuir equation has a good fit for all the adsorption systems. Langmuir monolayer adsorption capacities of the EDA, TETA and PEHA polymers were 548, 1003 and 1086mg/g, respectively. Adsorption mechanism was determined using FTIR, XPS, SEM, SEM Mapping and EDS. Adsorption mechanism is followed by ionic and surface complex formation mechanisms. Hydroxy chloro gold complexes were more interacted with nitrogen atoms of amine groups in polymers than nitrogen atoms in triazine rings. The adsorption capacity did not decrease after using all polymers five times. Furthermore, elution of the adsorbed Au (III) ions was made easily using 3% (m/v) thiourea solution in 1M HCl. From the results, it was concluded that EDA, TETA and PEHA polymers have a high gold uptake capacity and are highly efficient for the recycling of gold.
      Graphical abstract image

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.009
       
  • Bionanostructure-catalyzed one-pot three-component synthesis of
           3,4-dihydropyrimidin-2(1H)-one derivatives under solvent-free conditions
    • Authors: Ali Maleki; Reza Paydar
      Abstract: Publication date: Available online 4 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Ali Maleki, Reza Paydar
      In this work, chitosan/graphene oxide as a green bionanocomposite catalyst was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR) spectra, thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) analysis, atomic force microscopy (AFM) and scanning electron microscopy (SEM) images. Then, it was used as a nanocatalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives by a one-pot three-component condensation reaction of benzaldehyde, 1,3-ketoesters and urea in excellent yields and short reaction times under solvent-free conditions. The reaction work-up was simple and the catalyst could easily be separated from the reaction mixture and reused in subsequent reactions.
      Graphical abstract image

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.013
       
  • Adsorption of As (V) by poly (N-octyl-4-vinylpyridinium) bromide:
           Determination of As (V) by direct measurement of fluorescence on the solid
           phase
    • Authors: Javier González-Navarrete; María Inés Toral; Angel Leiva; Mehrdad Yazdani-Pedram; Hernán E. Ríos; Ximena Briones-Olarán; Marcela D. Urzúa
      Abstract: Publication date: Available online 2 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Javier González-Navarrete, María Inés Toral, Angel Leiva, Mehrdad Yazdani-Pedram, Hernán E. Ríos, Ximena Briones-Olarán, Marcela D. Urzúa
      Adsorption of As (V) by poly (N-octyl-4-vinylpyridinium) bromide (P4VPyC8), used as solid phase, was studied. Determination of As (V) was carried out by direct measurement of the fluorescence intensity on the solid phase. Adsorption variables were optimized for obtaining optimum values of pH and agitation time, where pH9.0 and 60min were established as optimum values. The adsorption of arsenic (V) was characterized by infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. It was found that the fluorescence of the solid phase increases as the concentration of arsenic increases. Linearity was observed in the concentration range 6.80 to 90.0μgL−1. The detection limit for determination of As (V) by this method was 2.24μgL−1 and the relative standard deviation (RSD) was 1.72%. The amount of retained As (V) was 0.154mg/g of solid phase. The determination of As (V) in a sample of tap water by this method was well compared with the value reported by an external certified laboratory. Therefore, the method of analysis proposed here could be used as a screening methodology for monitoring the fulfillment of the norm for arsenic concentration in tap water.
      Graphical abstract image

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.011
       
  • Soft-nanocoupling between silica and gold nanoparticles based on block
           copolymer
    • Authors: Qian Zhang; Shuhuan Yang; Tingting Zhu; Jung Kwon Oh; Pengfei Li
      Abstract: Publication date: Available online 5 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Qian Zhang, Shuhuan Yang, Tingting Zhu, Jung Kwon Oh, Pengfei Li
      A novel triblock copolymer of ABC type was synthesized by RAFT polymerization with good control and successfully acts as a specific “adhesive” to “glue” the SiO2 nanoparticles (NPs) and Au NPs together to make a hybrid. This method, with the coined name, soft-nanocoupling, is based on specific anchoring of organic groups onto the surface of inorganic nanoparticles with all-covalent interactions. SiO2 and Au NPs were used as a proof of concept in this contribution. For the triblock copolymer, namely POE-PGMA-PMPS {poly[oligo(ethylene oxide) methyl ether metharylate]-b-polyglycidyl methacrylate-b-poly[3-(methacryloxypropyl) trimethoxysilane]}, the POE block with oligo-PEG side chains was used to improve the dispersability in solvent media; the PGMA block that was further reacted with lipoic acid was used to anchor onto the Au NPs; and the silane-containing PMPS block can “grab” the SiO2 NPs. It was found that the resulting SiO2-Au hybrid has a corona shell of SiO2 NPs with Au NPs tightly embedded inside, and can even tolerate a harsh sonication process of 1h. Since the soft triblock copolymer functions as a bridge to couple Au and SiO2 NPs together, the process is called soft-nanocoupling. Compared to the conventional hard-coupling process, which requires specific case by case procedures, soft-nanocoupling is more straightforward, and especially can be designed in a modular way depending on the specific NPs used. With the well-established synthetic methodologies of NPs of single components to date, such as SiO2, Au, FexOy etc., all that is needed to make hybrid NPs is the proper design of a specific “glue” with anchoring moieties targeting the selected NPs. Thus, the soft-nanocoupling methodology affords a new platform for fabricating hybrid nano-objects from NPs using block copolymers.
      Graphical abstract image

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.012
       
  • Functionalization of 2-hydroxyethyl methacrylate-based polyHIPEs: Effect
           of the leaving group
    • Authors: Janja Majer; Muzafera Paljevac; Ema Žagar; Sebastijan Kovačič; Peter Krajnc
      Abstract: Publication date: Available online 1 November 2016
      Source:Reactive and Functional Polymers
      Author(s): Janja Majer, Muzafera Paljevac, Ema Žagar, Sebastijan Kovačič, Peter Krajnc
      Highly porous polymers based on 2-hydroxyethyl methacrylate (HEMA) have been successfully prepared through the high internal phase oil-in-water emulsions and further functionalized. Since functionalization of alcohol containing polymers through the direct nucleophilic substitution is rather difficult due to poor leaving ability of hydroxyl groups, the HEMA-based polymers have been modified through the halodehydroxylation and tosylation in order to obtain better leaving group residues as compared to the hydroxyl one. Conversion of hydroxyl groups into the corresponding alkyl halides and tosylates were found to be 78, 50, and 36% for the HEMA-Cl, HEMA-Br and HEMA-Ts, respectively. Further functionalization with the piperazine and tris(2-aminoethyl)amine through amine-alkylation was performed to test the leaving group ability of previously modified HEMA-Cl, HEMA-Br and HEMA-Ts polymers. Lower conversion rates for the HEMA-Cl or the HEMA-Br (between 18 and 41%) were found as compared to the HEMA-Ts (between 46 and 89%).

      PubDate: 2016-11-06T21:51:07Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.008
       
  • Improving the Hydrolytic Stability of Aryl Cyanate Esters by Examining the
           Effects of Extreme Environments on Polycyanurate Copolymers
    • Authors: Alasdair O. Crawford; Gabriel Cavalli; Brendan J. Howlin; Ian Hamerton
      Abstract: Publication date: Available online 29 October 2016
      Source:Reactive and Functional Polymers
      Author(s): Alasdair O. Crawford, Gabriel Cavalli, Brendan J. Howlin, Ian Hamerton
      Three cyanate ester monomer or oligomer species: 2,2-bis(4-cyanatophenyl)propane 1, 1-1-bis(4-dicyanatophenyl)ethane 2, and the oligomeric phenolic cyanate 3, are blended in various ratios to form binary mixtures (18 in total), formulated with copper(II) acetylacetonate (200 ppm) in dodecylphenol (1 % w/v active copper suspension) and cured (3 Kmin−1 to 150 °C + 1 hour; 3 Kmin−1 to 200 °C + 3 hours) followed by a post cure (3 Kmin−1 to 260 °C + 1 hour). Cured copolymers were exposed to environments of elevated relative humidity (75 % RH) and parallel immersion testing in H2O, H2SO4 (10 %) and NaOH (10 %) at 25 °C for a period of up to 2 years and accelerated ageing in boiling water (14 days). Periodic measurements are made of moisture gain along with infrared spectra and compared with cured homopolymers. Changes in mass are recorded periodically throughout exposure, prior to destructive thermo-mechanical analyses. Dynamic mechanical thermal analysis data comparing neat and exposed blends demonstrate the detrimental effect of moisture ingress whilst data from thermogravimetric analysis demonstrate no change in degradation onset between neat and exposed materials. An optimised blend of 1:1 of monomer units 1 and 2 was found to absorb less moisture than blends of different stoichiometry or between other respective monomeric units, consequently limiting the deleterious effect of moisture ingress.
      Graphical abstract image

      PubDate: 2016-10-30T21:45:44Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.007
       
  • Preparation of poly(glycolide-co-lactide)s through a green process:
           Analysis of structural, thermal, and barrier properties
    • Authors: Giuliana Gorrasi; Angelo Meduri; Paola Rizzarelli; Sabrina Carroccio; Giusy Curcuruto; Claudio Pellecchia; Daniela Pappalardo
      Abstract: Publication date: Available online 10 October 2016
      Source:Reactive and Functional Polymers
      Author(s): Giuliana Gorrasi, Angelo Meduri, Paola Rizzarelli, Sabrina Carroccio, Giusy Curcuruto, Claudio Pellecchia, Daniela Pappalardo
      We have successfully synthesized poly(lactide), poly(glycolide), and poly(lactide-co-glycolide) copolymers in bulk by ring-opening homo- and copolymerization of glycolide and L-lactide, using sodium hydride as the environmentally friendly and nontoxic initiator. Random copolymers were obtained, and the microstructure was characterized by nuclear magnetic resonance (1H and 13C NMR) and matrix-assisted laser desorption ionization mass spectrometry (MALDI MS). The mechanism of reaction was elucidated by analysis of the polymer end groups. Homopolymer and copolymers films and their blends were obtained, and their structure and physical properties were analyzed. Thermal degradation analysis showed superior characteristics of copolymers with respect to the blends. Transport properties of water vapor were also evaluated and correlated to the copolymer composition.

      PubDate: 2016-10-16T23:31:06Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.002
       
  • Preparation of small and photoresponsive polymer nanoparticles by
           intramolecular crosslinking of reactive star azo-polymers
    • Authors: Liang Ding; Chengshuang Wang; Ruiyu Jiang; Lingfang Wang; Wei Song
      Abstract: Publication date: Available online 14 October 2016
      Source:Reactive and Functional Polymers
      Author(s): Liang Ding, Chengshuang Wang, Ruiyu Jiang, Lingfang Wang, Wei Song
      Four-arm star azo-polymers with molecular weight control are prepared using the high selectivity of olefin cross-metathesis between acrylates and terminal olefins in the presence of multifunctional acrylates as the selective chain transfer agent. These reactive star azo-polymers are readily converted, by two different intramolecular crosslinking reactions of the end acrylate groups in dilute solution, to the new types of polymeric nanoparticles that exhibit distinct photoresponsive performance. Furthermore, the size and morphology of two types of polymeric nanoparticles show interesting and circular transformations when azo chromophore in nanoparticles underwent trans–cis–trans or cis–trans–cis isomerization cycles.
      Graphical abstract image

      PubDate: 2016-10-16T23:31:06Z
      DOI: 10.1016/j.reactfunctpolym.2016.10.004
       
  • Dissociation properties and behavior of active humic fractions dissolved
           in aqueous systems
    • Authors: Martina
      Abstract: Publication date: Available online 23 September 2016
      Source:Reactive and Functional Polymers
      Author(s): Martina Klučáková
      The function of humic acids in nature is strongly affected by their solubility and their ability to dissociate. This work is focused on the fraction of humic acids which is dissolved in water or rather the aqueous phase in humic-containing systems. This fraction can be rich in acidic functional groups which are the most active ones. The amount of the dissolved humic fraction can be considered to be the result of equilibrium between dissolved and undissolved humic substances. In this study, the concentration dependence of the dissociation constants was determined and analyzed. A maximum was observed for the dependence of the degree of dissociation on the concentration. In less concentrated leachates, less soluble humic particles with weaker functional groups were able to be dissolved. The weak functional groups have lower dissociation ability and they were able to remain in non-dissociated forms. The increase of humic contents in leachates caused smaller amounts of soluble fractions with the weakest functional groups to remain in an undissolved form, which led to the increase in the degree of dissociation. The increase in concentration of humic acids in the leachates caused the degree of dissociation decrease as a result of interactions between dissolved particles.

      PubDate: 2016-09-26T04:08:54Z
       
 
 
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